The Red Cross said it was focusing relief efforts on an estimated 20,000 people yet to get any assistance.

People are seen running out of Bali's Ngurah Rai International Airport, Indonesia August 9, 2018 in this still image taken from a video obtained from social media.

At a shelter in hard-hit Kayangan, new mother Rusnah, who like many Indonesians goes by one name, said she needed basic supplies for her children.

It's the third tremor to hit Lombok in the space of two weeks.

Authorities are gathering information from family members with missing relatives to determine how many more people may have been in the buildings when they collapsed, national search and rescue agency spokesman Yusuf Latif told AFP. "I do hope the government can help", she said.

Indonesia is prone to earthquakes because of its location on the 'Ring of Fire, ' an arc of volcanoes and fault lines in the Pacific Basin.

The island is a popular holiday spot and thousands of tourists have now left. In December 2004, a massive magnitude 9.1 natural disaster off Sumatra triggered a tsunami that killed 230,000 people in a dozen countries.